A fastener driving tool for driving fasteners, such as nails, drive screws, etc. is a tool in which a connected fastener assembly connecting multiple connected fasteners is stored in a magazine and the fasteners are fed to the nose section of the driving tool sequentially beginning with the first fastener so that the fasteners are driven continuously into workpieces.
Such fasteners are used not only to anchor wood to wood, but also to fasten liners or wood to concrete, to secure I-beams to thin steel sheets and to fasten denz glass (a plaster board-like material) to studs.
As methods for connecting fasteners to form a connected fastener assembly, various methods are known: for example, a stick type connecting method in which multiple fasteners are integrally connected to a straight connecting band made of a synthetic resin, a wire connecting method in which the shaft sections of fasteners are connected using two parallel metal wires by welding, and the so-called plastic sheet connecting method in which retaining pieces provided at constant intervals are bent in the same direction so as to protrude from the upper and lower ends of a connecting band made of a synthetic resin and having a thin sheet shape and fasteners are inserted into the upper and lower retaining pieces. As an example of the synthetic resin connecting method, the method disclosed in Patent document 1 is known. In addition, as an example of the plastic sheet connecting method, the method disclosed in Patent document 2 is known. Furthermore, a method in which fasteners are connected using a connecting sheet made of a synthetic resin is also known. This connecting sheet comprises retaining sections for allowing the shaft sections of fasteners to be passed through and connecting sections for connecting adjacent retaining sections (refer to Patent documents 3 and 4).    [Patent document 1] Japanese Patent Application Laid-Open Publication No. Sho 57-120713    [Patent document 2] Japanese Utility Model No. 2526455    [Patent document 3] Japanese Patent Application Laid-Open Publication No. 2005-90723    [Patent document 4] Japanese Utility Model Application Laid-Open Publication No. Hei 6-35623
However, the connected fastener assembly in which multiple fasteners are integrally connected to a straight connecting band made of a synthetic resin so as to be formed into a stick shape has a problem of being unable to be wound into a coil.
In addition, in the case of the connected fastener assembly according to the wire connecting method, wires are scattered at the time of driving, whereby there is a danger of striking and injuring human bodies and garbage is produced. Furthermore, the shaft sections of the fasteners are welded to wires in this method. In the case that the fasteners are hardened nails, for example, the strength thereof is lowered at the welded portions by heat during welding. When such nails are driven into high-strength concrete or the like, the nails are likely to buckle or fracture. Moreover, if the connected fastener assembly wound into a coil is dropped to the floor or ground inadvertently when the connected fastener assembly is loaded into the magazine of a fastener driving tool, the exterior of the coil may be deformed. If the exterior is deformed, it is difficult to restore the coil into its original shape. Besides, when the connected fastener assembly wound into a coil is carried, a finger is inserted into the center hollow portion of the coil. In this case, there is a danger that the finger is injured by the tip ends of the wires.
On the other hand, in the case of the connected fastener assembly according to the plastic sheet connecting method, each fastener is detached from the connecting band and driven at the time of driving. It is thus necessary to form an ejection hole for ejecting the connecting band remaining in the nose section of a fastener driving tool. Hence, the strength of the nose section lowers, and the connecting band becomes garbage and must be thrown away.
Furthermore, the connected fastener assembly obtained according to the method disclosed in Patent documents 3 and 4 in which fasteners are connected using a connecting sheet made of a synthetic resin is simple in structure. However, the connecting sections for connecting the adjacent fasteners are formed along the center line connecting the centers of these fasteners. Hence, when the connected fastener assembly is wound into a coil, if the first wound portion of the coil, that is, the portion having the smallest winding diameter, is attempted to be wound as small as possible in diameter, the connecting sections must be bent at an acute angle. However, if bent at an acute angle, the connecting sections are subjected to large stress, thereby being lowered in strength and whitened. As a result, the connecting sections may be broken owing to vibration or impact at the time of driving, thereby causing improper feeding. If the connecting sections are made to have a sufficient length, the connecting sections can be bent so that a coil having a small diameter is obtained. However, the pitch between the fasteners increases, and there is a problem that the number of fasteners to be connected is reduced. In addition, if the connecting sections are disposed along the center line of the connecting band, when the connected fastener assembly is loaded into the magazine of a fastener driving tool, the tip end of the feeding pawl of the tool interferes with the connecting section and cannot engage the center of the retaining section of the connecting band, and improper feeding may occur.